This invention relates primarily to the art of measuring a radiation transfer function of radiation paths which are characterizable as linear filters.
Presently utilized radar and sonar techniques for identifying and discriminating between different objects are incapable of providing good information as to the shape of the objects irradiated. The usual technique is to generate a radiation signal and direct that signal at an object with radiation reflected by the object being used to determine its range and velocity. The bandwidth of the radiation chosen is that with which the object reacts favorably as a reflector. The range and velocity information as to each object in an object space is then used to locate and identify the various objects. The transmitted signal used in these standard techniques is either an impulse, sinewave or some form of noise. In any of these specific techniques, the filtering effects of objects being irradiated are ignored and in fact are undesirable. There has been an attempt to characterize the shape of an object by examining the rise time of pulses reflected therefrom but this technique suffers from a very low signal-to-noise ratio.
Therefore, it is a primary object of the present invention to provide an improved technique for determining shape and other information of an object from the nature of the radiation returned therefrom.
It is a further object of the present invention to provide such a technique having a high signal-to-noise ratio, high resolution and at the same time being Doppler insensitive.
It is a more general object of the present invention to provide a technique for characterizing the nature of a radiation path transfer function by only a few parameters.